Cleaning large metal surfaces with abrasive blasting material (abrasive grit material) by abrasive blasting (or pressure blasting), such as by sandblasting, bead blasting, etc., is well known in the related art. The most commonly used type of abrasive blasting media currently used is silica sand, fine glass beads, steel shot, steel grit, stainless steel shot, cut wire, grit or similar sized pellets, etc. It is possible to repeatedly use the same abrasive blasting material (or media) several times, if the abrasive blasting material is properly cleaned between each use.
During blasting operations using prior art abrasive blasting equipment, the operator directs a mixture of pressurized air and the abrasive blasting media through a nozzle to the area requiring cleaning or blasting. The abrasive blasting media is stored in a blast pot (or abrasive media holding tank) containing the abrasive media that is pressurized with air. The nozzle is typically connected to the blast pot through a length of flexible hose so that the nozzle may be used at various distances that are remote from the blast pot.
Prior art blasting equipment utilizes an on/off control so that the blast stream can be stopped or started with no variation in the amount of particulate flow or pressure from the blast pot. In order to regulate the flow of particulate, the operator must stop the blasting operation and return to the blast pot so that the flow setting of the blast pot can be manually adjusted. The operator must then return to the blast nozzle, test the particulate flow from the nozzle and determine whether the particulate flow is adequate or optimal. If the flow is not optimal, the operator must return to the blast pot and continue this process until the proper particulate flow is achieved. As can be seen, this is an inconvenient and time consuming process. Furthermore, during a job, different degrees of particulate flow may be required or necessary at any given time to perform the blasting operation. In some instances, the particulate flow may be optimal for certain areas, but too low or too high for others. In many instances, proper optimization may not be seriously pursued by the operator because of the inconvenience of adjusting the abrasive flow. This may result in abrasive being wasted because it is either insufficient or excessive for the particular area being blasted or it provides an inadequate blasting job.
Accordingly, what is therefore needed is a means for abrasive blasting wherein the amount of blasting media can be controlled remotely from the blast pot and during the blasting operation to overcome these shortcomings.